Messages

1

Problem dxf files etc... / Re: Can't Save Gcode File

« on: January 15, 2008, 19:05:45 pm »

I thought that when I wanted to make the code that the program would ask me those questions.

Unfortunately Chris, any CAM program you will encounter will need to know how deep you wish to machine each piece of geometry, whether you wish to engrave/profile/mill/drill, whether you wish to do an inside/outside profile etc. etc.

Have a look at the tutorials here:
http://www.brusselsprout.org/CAMBAM/tutorials/

2

CamBam help (General usage) / Re: spindle and cut directions

« on: January 05, 2008, 00:09:09 am »

Whilst I currently maintain some semblance of sobriety, Spiral Up-cut Vs Down-cut Vs Combination bits also deserve a mention.

These types of woodworking bits are normally designed for CW rotating spindles and each serve their own purpose.

Up-cut bits:

These bits are mostly similar to a drill bit, where the design readily allows for plunge cuts and an upward path within the flutes, for chips to be extracted from the material. Particularly suitable for machining grooves (dado's), holes, etc. where the upper surface finish doesn't need to be perfect, but any through-machining of the material requires a clean profile finish on the lower surface.

Down-cut bits:

These bits are designed in the same fashion as a drill bit, but the flutes are twisted in the opposite direction. This has the effect of pushing chips downwards and as such, this cutter is not particularly well-suited for plunging, holes, grooves etc. as the chips can become compacted. Where this type of bit shines, is when a clean profile finish is required upon the top surface of a workpiece.

Combination bits:

These bits are a mixture of both an Up-cut & Down-cut bit - the lower portion is Up-cut and the upper portion is Down-cut. This has the advantage of forcing chips toward the middle of the workpiece and the bit is particularly well-suited to edge-machining materials with a laminated upper & lower surface.

3

CamBam help (General usage) / Re: spindle and cut directions

« on: January 04, 2008, 23:11:20 pm »

I'll chime in here with regard to a hand-held router...

This example assumes the following:
1. You are standing in front of a bench/table/stand of some form, holding your workpiece.
2. You have the router in front of you, bit pointing down.
3. The edge of the material you wish to, erm, route, is facing you. 


Looking from above, as is the case when using a hand-held router, the spindle rotates clockwise and the cut is taken from left to right, resulting with the material being removed from the workpiece at the opposite side of the bit from yourself. This is a 'conventional' cut - the cutting action tries to force the bit out from the material and you control the router by feeding it back into the material.

This approach works for all outside profiles, moving the router in a CCW direction.

To keep the cutter in 'conventional' mode for an inside profile, the spindle is still turning CW, but the router direction is reversed in regard to your body position - right to left - since you still need to feed left-to-right, but you are on the wrong side of the material. Confused yet?

Now, using the same 3 bullet points as above on an outside profile, moving the router from right-to-left results in a 'climb' cut, where the cutting bit tries to "climb" along the workpiece...the bit is rotating CW and digs into the material upon each cut, and with the aid of 'the driver', is allowed to draw itself along. The result? - A poorer finish on machines with any amount of slop.

Soooooo, to sort-of answer EL's question:
With a CW rotating spindle (Looking from above), profiling the inside of a circle, square, triangle etc. generally requires a CW (Conventional) cut.

You can modify the cut direction from the 'SpindleControl' submenu within a MOP. CamBam assumes a CW spindle and seems to default to 'Conventional' cuts.

4

How to's and tutorials / Re: A little Handbook of Useful Information

« on: January 04, 2008, 19:14:36 pm »

I'm sure there are quite a few of us who have wanted to do something like this and add it to the forum, but have not yet found enough spare time to do so, myself included.

R, thanks for collating some useful info.

5

CamBam help (General usage) / Re: G03 corner problem

« on: December 24, 2007, 22:14:16 pm »

Kudos to you guys building your own drivers/PSU's. I had the 'disposable' cash and bought a kit, because I wanted the machine running NOW!!!, if not sooner  .

I do enjoy building things, but I like to have the whole kit in front of myself and build it at one sitting...however long it takes. Fragmented projects tend to wear thin very quickly.

6

CamBam help (General usage) / Re: G03 corner problem

« on: December 24, 2007, 15:13:40 pm »

Pipped by Andy! 

7

CamBam help (General usage) / Re: G03 corner problem

« on: December 24, 2007, 15:12:59 pm »

Just taking a wild stab here:

Have a look in 'Configure - General Config' and check the "Arc Factor" (Default is 1).
From the TurboCNC help file..."Arc Factor: This option provides a method of adjusting timing loops used when cutting an arc to the speed of the computer. Values less than one increase the loop speed, those above one decrease it. If you notice lost steps while cutting arcs decrease this value to 0.8 or less."

Also, check the setting in 'Machine' (Default is 'Custom', but there are multiple settings, one of which is for Mill/Drill)

Under 'Configure - Configure Axes', what are your settings for 'Accel, Start Vel & Max Vel'?
A slow Accel would not be that apparent on a linear move along one axis, but arcs & diagonals can result in tiny start/stop movements with a slow Accel due to the steppers ramping up & down as Andy pointed out earlier.

Are your steppers all the same, or are they mixed? I believe (but I could be wrong) that using mixed steppers on arcs & diagonals causes the slowest stepper settings to be used for both axes.

8

CamBam help (General usage) / Re: G03 corner problem

« on: December 23, 2007, 21:40:00 pm »

Have a quick peek at these posts/threads:
http://www.forum.cambam.org/index.php/topic,168.msg1135.html#msg1135
http://www.forum.cambam.org/index.php/topic,168.msg1187.html#msg1187

and also check the settings in TurboCNC for Absolute/Incremental mode in 'Configure - RS 274 Dialect - Arc IJK Offsets'. I believe it should be set to 'Incremental'...

9

CamBam help (General usage) / Re: Drop off surface help ?

« on: December 23, 2007, 21:28:26 pm »

Did you get to cut the part successfully yet Chris?

10

CamBam help (General usage) / Re: Strange "pimple" on Text Pocketing MOP

« on: December 21, 2007, 18:59:46 pm »

...Just checked the settings in both TCNC and CamBam and found what I was looking for.  Please disregard.

Fly,

if you find Incremental/Absolute settings that consistently work with a CamBam & TurboCNC setup, could you please post them for future reference..and the planned help file/tutorials.

Thanks.

11

Members Projects / Re: When Laptops go to sleep -- pocket letters in ellipse

« on: December 19, 2007, 20:51:51 pm »

Uuurgh! That looked to be a nice piece of stock with some pretty figuring too.

12

CamBam help (General usage) / Re: Strange "pimple" on Text Pocketing MOP

« on: December 19, 2007, 20:47:41 pm »

( This file was created automatically using CamBam )
( http://www.brusselsprout.org/CAMBAM )
( 12/19/2007 7:25:09 PM )
( T0 : 0.125 )
G20
G90
G64
G00 Z0.5
( MOPPocket_2 )
( T0 : 0.125 )
M06 T0
M03
G00 X-4.883411 Y-0.196454
G01 F3 Z-0.125
G02 F4 X-4.806295 Y-0.583802 I-0.842415 J-0.369065
G03 X-4.80634 Y-0.593246 I0.312438 J-0.006212
G02 X-4.859831 Y-0.92819 I-1.009984 J-0.010446
G02 X-4.863068 Y-0.93719 I-0.759124 J0.26794
G00 Z0.5
G00 X-5.015771 Y0.086852
G01 F3 Z-0.125
G02 F4 X-4.890748 Y-0.072532 I-0.474962 J-0.501294
G03 X-4.889164 Y-0.075274 I0.228067 J0.129967
G02 X-4.756305 Y-0.584796 I-0.836662 J-0.490245
G03 X-4.756342 Y-0.592729 I0.262448 J-0.005218
G02 X-4.81258 Y-0.944542 I-1.059982 J-0.010963
G02 X-4.957665 Y-1.202245 I-0.806375 J0.284293
G00 Z0.5
G00 X-5.897336 Y-1.719727
G01 F3 Z-0.125
G01 F4 X-6.576546
G03 X-6.51786 Y-1.656232 I-0.157346 J0.204298
G03 X-6.516321 Y-1.653746 I-0.05236 J0.034127
G03 X-6.485757 Y-1.571833 I-0.218112 J0.128045
G03 X-6.485672 Y-1.571367 I-0.061452 J0.0114
G03 X-6.46943 Y-1.363896 I-1.050058 J0.186576
G01 Y0.159897
G03 X-6.47649 Y0.307981 I-1.354876 J0.009617
G03 X-6.476506 Y0.30814 I-0.062173 J-0.006387
G03 X-6.490089 Y0.386 I-0.580315 J-0.061123
G03 X-6.530774 Y0.474503 I-0.222421 J-0.048645
G03 X-6.534092 Y0.478537 I-0.049888 J-0.037648
G03 X-6.574261 Y0.515331 I-0.205026 J-0.183504
G01 X-5.910587
G03 X-5.910219 Y0.515332 I0 J0.0625
G02 X-5.51015 Y0.493591 I0.01964 J-3.33043
G02 X-5.315241 Y0.459704 I-0.218512 J-1.834278
G03 X-5.315036 Y0.459657 I0.013988 J0.060915
G02 X-5.131331 Y0.400384 I-0.237462 J-1.050278
G02 X-4.716982 Y0.02649 I-0.359402 J-0.814826
G03 X-4.716605 Y0.025838 I0.054302 J0.030945
G02 X-4.556344 Y-0.588772 I-1.009221 J-0.591356
G03 X-4.556353 Y-0.590661 I0.062488 J-0.001242
G02 X-4.62357 Y-1.009938 I-1.259971 J-0.013032
G02 X-4.839194 Y-1.370915 I-0.995384 J0.349689
G02 X-5.283519 Y-1.646543 I-0.727332 J0.676544
G03 X-5.284279 Y-1.646774 I0.017807 J-0.05991
G02 X-5.545985 Y-1.703282 I-0.447623 J1.4388
G03 X-5.54605 Y-1.70329 I0.007711 J-0.062022
G02 X-5.711119 Y-1.717455 I-0.263363 J2.100221
G00 Z0.5

The line in red appears to be at the point where your machining goes awry on the letter D...

I previously didn't fully understand why G02's and G03's would be included for a continuously sweeping arc in one direction..  until now.

Enclosing the above green G03 G-code lines in parenthesis (disabling) has no adverse effect on the toolpath which cuts the RH curved outer edge of the "D", but the reason that they are present is due to transitional movements from the end of one arc segment, to the start of the next.

This doesn't explain why the error occurs at that particular point, but may help to alleviate the confusion I and other's may have had with regard to G02 & G03 moves on the same curved toolpath.



Anywhoo, it was previously suggested that Incremental/Absolute mode could have something to do with this type of machining error in Tcnc...is it possible to quick-test both modes on a sample of foam etc. and report back?

13

CamBam help (General usage) / Re: Strange "pimple" on Text Pocketing MOP

« on: December 18, 2007, 22:16:20 pm »

A .cb file could be helpful too, to analyse.

14

CamBam help (General usage) / Re: Text in a circle

« on: December 17, 2007, 22:58:16 pm »

AFAIK, laptop screens aren't susceptible to screen burn, so configuring it not to go to screen-saver/power management when using AC power will prevent your problem. I still use a power management setting when using the batteries though.

I only use flat screens on both of my desktop machines and none of them go to screen savers (one is a dual-screen setup). They are on most of the time and can sometimes sit idle for prolonged periods. No problems with the screens so far...

Maybe not very good for the carbon footprint but then again, neither is having to waste power re-cutting a part. 

15

CamBam help (General usage) / Re: Text in a circle

« on: December 17, 2007, 18:21:23 pm »

I don't quite understand the statement

You can also select the inner A triangle and pocket that at the same time with one mop.

Can you explain please?

I'll try...
It appears you have already noted that an 'inside' pocketing operation is required for both operations upon the geometry, to leave the letter body raised... selecting one section of geometry (the circle & the 'A' outline), then holding CTRL + clicking the inner triangle of the 'A', or vice-versa, will select both of them and allow you to assign the same Machining OPeration automatically.

If you wish to cut to a depth which will require multiple passes of the cutting tool, you should make sure that DepthFirst is selected in the CUT ORDERING section of the lower left pane, otherwise the cutter will have to swap back and forth between each region if LevelFirst is selected.

Selecting multiple regions that require identical operations is kinda like doing separate MOP's for each region, but eliminates having to input the information twice or more. 

Oops, one other comment.  I imported an ellipse DXF and centered it on the origin with the transformation  (I did not have it on the origin when I made it in the CAD program, will remember to do that right next time), no problem.  Then I inserted some text, and transformed it to get it centered on the origin and in the ellipse (it was .2" too low to be centered on the origin).  Then when I did the polyline/region business per the instructions, the text moved back to its original location.  I moved the ellipse a bit to center it around the text again, and that seemed to hold.

Not sure why it did that?

--R

I'm not sure either. Perhaps someone else can explain this?